Blender proportional edit slider gone in 2.8 and above?
Solution discovered by OP:
I found a great solution. On my Wacom Intuos Pro pen tablet, my touch ring set to &quot;ZOOM&quot; is a perfect substitute to a mouse scroll wheel. Anyone using a pen tablet (with a touch ring) instead of a mouse can do this to adjust the spread of the proportional edit! Problem solved
For those whom this solution does not help:
The slider can be found in the Operator Panel. You can only adjust the size after the fact though (as far as I know), and the selection circle is not visible, so it's not ideal. Nevertheless it's there: